Having to use another keyboard to unlock a secondary computer over Synergy can be annoying. Synergy let’s you unlock a secondary computer by sending CTRL + ALT + Pause/Break, however a default Windows setting prevents this from working. To allow this follow these steps.

1. Launch the local group policy editor by clicking start and enter “gpedit.msc”.

4. Check the “Enabled” box and then select “Services” from the dropdown.

5. Click OK.

Unfortunately you will not be able to lock the secondary computer with this same command. For faster locking I recommend creating a shortcut with the following target:
C:\Windows\System32\rundll32.exe user32.dll,LockWorkStation